100Cr6 chrome steel submitted to martensitic hardening and tempering is usually adopted for particular industrial applications such as bearings, rings and rollers. These parts are often subjected to dynamic stresses in different fields of engineering and, consequently, it is important to know the residual stresses involved, especially in correspondence of critical zones, particularly fatigue-stress and/or crack sensitive. In this paper, the residual stress investigation by neutron diffraction in a 100Cr6 chromium steel ring – before and after the introduction of a hub fixed by orbital rolling – is presented. The results supply information on the real residual stress status, showing its enhancement due to the installation of the hub and the successive rolling operation. The achieved data can support the manufacturing process in order to improve the life assessment of the considered component. K e y w o r d s: 100Cr6 steel, rings, martensitic hardening, tempering, residual stress, neutron diffraction
{"title":"Residual stresses determination by neutron diffraction in a 100Cr6 chromium steel bearing ring","authors":"M. Rogante, G. Martinat, P. Mikula, M. Vrána","doi":"10.4149/km_2013_5_275","DOIUrl":"https://doi.org/10.4149/km_2013_5_275","url":null,"abstract":"100Cr6 chrome steel submitted to martensitic hardening and tempering is usually adopted for particular industrial applications such as bearings, rings and rollers. These parts are often subjected to dynamic stresses in different fields of engineering and, consequently, it is important to know the residual stresses involved, especially in correspondence of critical zones, particularly fatigue-stress and/or crack sensitive. In this paper, the residual stress investigation by neutron diffraction in a 100Cr6 chromium steel ring – before and after the introduction of a hub fixed by orbital rolling – is presented. The results supply information on the real residual stress status, showing its enhancement due to the installation of the hub and the successive rolling operation. The achieved data can support the manufacturing process in order to improve the life assessment of the considered component. K e y w o r d s: 100Cr6 steel, rings, martensitic hardening, tempering, residual stress, neutron diffraction","PeriodicalId":18519,"journal":{"name":"Metallic Materials","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75533780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cast alloy IN625 is a candidate Ni-based alloy for advanced ultra-supercritical (A-USC) power plants. In order to investigate the influence of Mo on δ phase precipitation, the heat treatment experiments on the Mo series of alloys were carried out at 750 ◦ C (the service temperature of A-USC power plants) up to 17,000 h, and effects of δ phase on the tensile properties were also studied. The results show that lots of δ phase precipitated after long-term aging at 750 ◦ C and the Mo content has a weak effect on the precipitation of the δ phase. With the increasement of δ phase content, the strength of alloys after aging at 750 ◦ C for up to 5,000 h increased nearly linearly with the increasing aging time while the elongation was affected by δ precipitation to a relatively limited extent. It is suggested that the δ phase serves as a strengthening phase in cast alloy IN625.
{"title":"Effect of Mo on δ phase precipitation and tensile properties in cast alloy IN625","authors":"Y. Mu, M. Na, C. Wang, Q. Xu","doi":"10.4149/KM_2021_2_93","DOIUrl":"https://doi.org/10.4149/KM_2021_2_93","url":null,"abstract":"Cast alloy IN625 is a candidate Ni-based alloy for advanced ultra-supercritical (A-USC) power plants. In order to investigate the influence of Mo on δ phase precipitation, the heat treatment experiments on the Mo series of alloys were carried out at 750 ◦ C (the service temperature of A-USC power plants) up to 17,000 h, and effects of δ phase on the tensile properties were also studied. The results show that lots of δ phase precipitated after long-term aging at 750 ◦ C and the Mo content has a weak effect on the precipitation of the δ phase. With the increasement of δ phase content, the strength of alloys after aging at 750 ◦ C for up to 5,000 h increased nearly linearly with the increasing aging time while the elongation was affected by δ precipitation to a relatively limited extent. It is suggested that the δ phase serves as a strengthening phase in cast alloy IN625.","PeriodicalId":18519,"journal":{"name":"Metallic Materials","volume":"88 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85774464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Damage and oxidation resistance are properties characterizing Ni-based superalloys. How-ever, besides the alloy composition, the mentioned properties depend on structural features such as grain and precipitates size. Surface structure refinement via laser beam (LB) and electron beam (EB) was performed on IN 713LC superalloy. The influence of both the treatments on material microstructure, chemical composition, microhardness, and oxidation resistance was examined. Both the treatments resulted in a refined structure of the remelted zone. A homogeneous 30–43 µ m thick remelted zone was created by EB, while a non-homogeneous (semi-circular track) remelted zone (22–86 µ m) was created by LB. EB treatment resulted in higher surface roughness; however, a smaller amount of cracks on the treated sample surface was observed compared to the LB treatment. An increase of surface microhardness by 38 % compared to the as-received material was reached regardless of the used treatment method. The impact of the treatment on oxidation resistance was studied after exposure to 800 ◦ C for 24, 48, 72, and 96 hours in the ambient air. The created oxide layer consisted of internal Al 2 O 3 and external Cr 2 O 3 + NiCr 2 O 4 layer. The oxide layer thickness differs in time; however, comparable oxide layer thickness was measured on all samples after 96 hours of oxidation.
{"title":"Comparison of the effect of EB and LB surface treatment on structural characteristics of IN 713LC superalloy","authors":"E. Švábenská, V. Horník, S. Fintová","doi":"10.4149/KM_2021_2_119","DOIUrl":"https://doi.org/10.4149/KM_2021_2_119","url":null,"abstract":"Damage and oxidation resistance are properties characterizing Ni-based superalloys. How-ever, besides the alloy composition, the mentioned properties depend on structural features such as grain and precipitates size. Surface structure refinement via laser beam (LB) and electron beam (EB) was performed on IN 713LC superalloy. The influence of both the treatments on material microstructure, chemical composition, microhardness, and oxidation resistance was examined. Both the treatments resulted in a refined structure of the remelted zone. A homogeneous 30–43 µ m thick remelted zone was created by EB, while a non-homogeneous (semi-circular track) remelted zone (22–86 µ m) was created by LB. EB treatment resulted in higher surface roughness; however, a smaller amount of cracks on the treated sample surface was observed compared to the LB treatment. An increase of surface microhardness by 38 % compared to the as-received material was reached regardless of the used treatment method. The impact of the treatment on oxidation resistance was studied after exposure to 800 ◦ C for 24, 48, 72, and 96 hours in the ambient air. The created oxide layer consisted of internal Al 2 O 3 and external Cr 2 O 3 + NiCr 2 O 4 layer. The oxide layer thickness differs in time; however, comparable oxide layer thickness was measured on all samples after 96 hours of oxidation.","PeriodicalId":18519,"journal":{"name":"Metallic Materials","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88811629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The effect of co-addition of La and Nd on microstructures and mechanical properties of squeeze-cast Mg-Al-Zn-La-Nd alloys","authors":"P. Cui, Z. Ji, M. Hu, H. Xu, X. Zhang, T. Zhang","doi":"10.4149/km_2021_5_291","DOIUrl":"https://doi.org/10.4149/km_2021_5_291","url":null,"abstract":"","PeriodicalId":18519,"journal":{"name":"Metallic Materials","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87020330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of tool rotational and welding speeds on the microstructure and mechanical properties of friction stir welded AA5086-O was studied. Optical metallography and scanning transmission electron microscopy were used to characterize the microstructure of different zones of welds. The relationship between residual stress profiles and local mechanical properties of different weld zones was studied using X-ray diffraction (XRD) and Digital Image Correlation (DIC), respectively. A lower speed ratio (tool rotational speed/tool traverse speed – ω/v) reduced the grain size and increased hardness and tensile strength in the stir zone (SZ). The longitudinal and transversal residual stress profiles in the welds show a good correlation between the (ω/v) ratio (welding heat input) and local mechanical properties of different zones of FSWed joints. The weld produced with the highest heat input showed the lowest residual stress. Also, the residual stresses of different weld zones increased with their yield stress. K e y w o r d s: friction stir welding, AA5086 aluminium alloys, microstructures, mechanical properties, residual stress
{"title":"Effect of welding parameters on microstructure, mechanical properties and residual stress fields of friction stirwelds on AA5086","authors":"H. J. Aval, A. Loureiro","doi":"10.4149/km_2014_1_51","DOIUrl":"https://doi.org/10.4149/km_2014_1_51","url":null,"abstract":"The effect of tool rotational and welding speeds on the microstructure and mechanical properties of friction stir welded AA5086-O was studied. Optical metallography and scanning transmission electron microscopy were used to characterize the microstructure of different zones of welds. The relationship between residual stress profiles and local mechanical properties of different weld zones was studied using X-ray diffraction (XRD) and Digital Image Correlation (DIC), respectively. A lower speed ratio (tool rotational speed/tool traverse speed – ω/v) reduced the grain size and increased hardness and tensile strength in the stir zone (SZ). The longitudinal and transversal residual stress profiles in the welds show a good correlation between the (ω/v) ratio (welding heat input) and local mechanical properties of different zones of FSWed joints. The weld produced with the highest heat input showed the lowest residual stress. Also, the residual stresses of different weld zones increased with their yield stress. K e y w o r d s: friction stir welding, AA5086 aluminium alloys, microstructures, mechanical properties, residual stress","PeriodicalId":18519,"journal":{"name":"Metallic Materials","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90812878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates effects of TIG welding and welding heat input on microstructure, hardness, tensile strength, fracture mechanism, and electrical resistance of Nichrome 8020 to evaluate its efficiency after welding, especially as a heating element. The post-weld microstructure of the alloy remained austenitic. The microstructure of fusion zone consisted of columnar dendrites, equiaxed dendrites, and intermetallic carbonitrides. These precipitates nucleated and grew among subgrain boundaries. Because of grain growth, hardness and tensile strength decreased after welding, and by increasing welding heat input, these mechanical properties decreased more severely. Fractography analysis showed that fracture surfaces of all the welded samples included both brittle and ductile features. Despite grain growth, which occurred as a result of the welding process, the electrical resistance of Nichrome 8020 increased slightly after welding. No signs of welding cracks and topologically close-packed phases were observed in the heat affected zone and fusion zone of any sample. K e y w o r d s: nichrome, welding, microstructure, mechanical properties, fractography, electrical resistance
{"title":"Effects of TIG welding process on microstructure, electrical resistance and mechanical properties of Nichrome 8020","authors":"S. Afkhami, A. Halvaee","doi":"10.4149/km_2016_3_289","DOIUrl":"https://doi.org/10.4149/km_2016_3_289","url":null,"abstract":"This study investigates effects of TIG welding and welding heat input on microstructure, hardness, tensile strength, fracture mechanism, and electrical resistance of Nichrome 8020 to evaluate its efficiency after welding, especially as a heating element. The post-weld microstructure of the alloy remained austenitic. The microstructure of fusion zone consisted of columnar dendrites, equiaxed dendrites, and intermetallic carbonitrides. These precipitates nucleated and grew among subgrain boundaries. Because of grain growth, hardness and tensile strength decreased after welding, and by increasing welding heat input, these mechanical properties decreased more severely. Fractography analysis showed that fracture surfaces of all the welded samples included both brittle and ductile features. Despite grain growth, which occurred as a result of the welding process, the electrical resistance of Nichrome 8020 increased slightly after welding. No signs of welding cracks and topologically close-packed phases were observed in the heat affected zone and fusion zone of any sample. K e y w o r d s: nichrome, welding, microstructure, mechanical properties, fractography, electrical resistance","PeriodicalId":18519,"journal":{"name":"Metallic Materials","volume":"86 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80619091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of heat treatments on microstructure and mechanical properties of Al0.5CoCr FeNi complex concentrated alloy (CCA) was studied. The CCA was prepared by vacuum induction melting of pure elements and solidification in ceramic crucibles. The as-solidified alloy was subjected to heat treatments consisting of solid solution annealing, water quenching and precipitation hardening. The microstructure of the as-solidified alloy consists of fcc(A1) dendrites and an interdendritic region composed of bcc(B2), bcc(A2) and fcc(A1) phases. The solution annealing followed by water quenching and ageing at 800 and 900◦C leads to the precipitation of needle-like bcc(B2) particles in fcc(A1) dendrites and the formation of the interdendritic region composed of bcc(B2) and fcc(A1) phases. The volume fraction of needle-like bcc(B2) precipitates increases with increasing ageing time and decreasing ageing temperature. The size of bcc(B2) precipitates increases with increasing ageing time and ageing temperature. Vickers microhardness, Vickers hardness and room temperature yield strength of the heat-treated alloy increase with decreasing ageing temperature and increasing ageing time up to 5 h and then decrease at a longer ageing time up to 25 h. K e y w o r d s: complex concentrated alloys, precipitation hardening, heat treatment, microstructure, mechanical properties
{"title":"Effect of heat treatments on microstructure and mechanical properties of Al0.5CoCrFeNi complex concentrated alloy","authors":"J. Lapin, M. Makwana, A. Klimová","doi":"10.4149/KM_2021_2_79","DOIUrl":"https://doi.org/10.4149/KM_2021_2_79","url":null,"abstract":"The effect of heat treatments on microstructure and mechanical properties of Al0.5CoCr FeNi complex concentrated alloy (CCA) was studied. The CCA was prepared by vacuum induction melting of pure elements and solidification in ceramic crucibles. The as-solidified alloy was subjected to heat treatments consisting of solid solution annealing, water quenching and precipitation hardening. The microstructure of the as-solidified alloy consists of fcc(A1) dendrites and an interdendritic region composed of bcc(B2), bcc(A2) and fcc(A1) phases. The solution annealing followed by water quenching and ageing at 800 and 900◦C leads to the precipitation of needle-like bcc(B2) particles in fcc(A1) dendrites and the formation of the interdendritic region composed of bcc(B2) and fcc(A1) phases. The volume fraction of needle-like bcc(B2) precipitates increases with increasing ageing time and decreasing ageing temperature. The size of bcc(B2) precipitates increases with increasing ageing time and ageing temperature. Vickers microhardness, Vickers hardness and room temperature yield strength of the heat-treated alloy increase with decreasing ageing temperature and increasing ageing time up to 5 h and then decrease at a longer ageing time up to 25 h. K e y w o r d s: complex concentrated alloys, precipitation hardening, heat treatment, microstructure, mechanical properties","PeriodicalId":18519,"journal":{"name":"Metallic Materials","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90400273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, the thermal conductivity, enthalpy of fusion, specific heat capacity, and thermal diffusivity of the Al-5.5Zn-2.5Mg (wt.%) ternary alloy have been investigated. Thermal conductivity of as-cast Al-5.5Zn-2.5Mg alloy was measured using comparison cut bar method in the temperature range of 323–723 K. With the increase of temperature, thermal conductivity decreased gradually in as-cast Al-5.5Zn-2.5Mg alloy. The thermal temperature coefficient was calculated from the respective graph. The enthalpy of fusion and the specific heat capacity during the transformation were also determined. Thermal diffusivity changes were calculated as a function of temperature through the obtained thermal data. It was observed that thermal diffusivity values decreased with increasing temperature.
{"title":"Determination of the thermal properties of Al-Zn-Mg alloy","authors":"E. Çadırlı, E. Üstün, U. Büyük, H. Kaya","doi":"10.4149/KM_2021_1_59","DOIUrl":"https://doi.org/10.4149/KM_2021_1_59","url":null,"abstract":"In this work, the thermal conductivity, enthalpy of fusion, specific heat capacity, and thermal diffusivity of the Al-5.5Zn-2.5Mg (wt.%) ternary alloy have been investigated. Thermal conductivity of as-cast Al-5.5Zn-2.5Mg alloy was measured using comparison cut bar method in the temperature range of 323–723 K. With the increase of temperature, thermal conductivity decreased gradually in as-cast Al-5.5Zn-2.5Mg alloy. The thermal temperature coefficient was calculated from the respective graph. The enthalpy of fusion and the specific heat capacity during the transformation were also determined. Thermal diffusivity changes were calculated as a function of temperature through the obtained thermal data. It was observed that thermal diffusivity values decreased with increasing temperature.","PeriodicalId":18519,"journal":{"name":"Metallic Materials","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73438355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Čavojský, V. Nagy-Trembošová, N. Beronská, M. Nosko
{"title":"Hot extrusion of magnesium/hydroxyapatite composites prepared by powder metallurgy","authors":"M. Čavojský, V. Nagy-Trembošová, N. Beronská, M. Nosko","doi":"10.4149/km_2021_5_315","DOIUrl":"https://doi.org/10.4149/km_2021_5_315","url":null,"abstract":"","PeriodicalId":18519,"journal":{"name":"Metallic Materials","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76783964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of rare earth Y on properties of Zr-based bulk metallic glasses","authors":"J. Li, C. Li, S. Wang, H. Wang, S. Kou","doi":"10.4149/KM_2021_1_11","DOIUrl":"https://doi.org/10.4149/KM_2021_1_11","url":null,"abstract":"","PeriodicalId":18519,"journal":{"name":"Metallic Materials","volume":"105 1","pages":"11-20"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75645253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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